This proposal examines the role of platelet lipids in the regulation of platelet function. The major focus of the proposal is the study of platelet phospholipases as determinants of arachidonic acid release and subsequent transformation by the oxygen-inserting enzymes of the platelet. The major goal of the proposal is the exploration of the control and functional significance of the plasmalogen phosphatidylethanolamine pathway of arachidonic acid metabolism in human platelets. Major techniques will include: the study of arachidonic acid metabolism in intact platelets, and in broken cell systems using thin-layer, paper, and high pressure liquid chromatographic methods for lipid resolution and analysis. These studies will further our knowledge of platelet function and of the platelet contribution to hemorrhagic and thrombotic diseases.